Polycom RealPresence 800s Administrator's Manual page 397

RealPresence Collaboration Server (RMX) 800s/Virtual Edition Administrator's Guide
Field
Type
Audio / Video
TOS
Polycom®, Inc.
Description
DiffServ and Precedence are two methods for encoding packet priority. The
priority set here for audio video and IP Signaling packets should match the
priority set in the router.
• DiffServ: Select when the network router uses DiffServ for priority encoding.
The default priorities for both audio and video packets is 0x31. These values
are determined by the QOS_IP_VIDEO and QOS_IP_AUDIO flags in the
system.cfg file.
The default priority for Signaling IP traffic is 0x00 and is determined by the
QOS_IP_SIGNALING flag in the system.cfg file.
For more information Modifying System Flags
• Precedence: Select when the network router uses Precedence for priority
encoding, or when you are not sure which method is used by the router.
Precedence should be combined with None in the TOS field.
The default priority is 5 for audio and 4 for video packets.
Note: Precedence is the default mode as it is capable of providing priority
services to all types of routers, as well as being currently the most common
mechanism.
You can prioritize audio and video IP packets to ensure that all participants in
the conference hear and see each other clearly. Select the desired priority. The
scale is from 0 to 5, where 0 is the lowest priority and 5 is the highest. The
recommended priority is 4 for audio and 4 for video to ensure that the delay for
both packet types is the same and that audio and video packets are
synchronized and to ensure lip sync.
Select the type of Service (TOS) that defines optimization tagging for routing the
conferences audio and video packets.
• Delay: The recommended default for video conferencing; prioritized audio
and video packets tagged with this definition are delivered with minimal delay
(the throughput of IP packets minimizes the queue sequence and the delay
between packets).
• None: No optimization definition is applied. This is a compatibility mode in
which routing is based on Precedence priority settings only. Select None if
you do not know which standard your router supports.
411